Carburetor



Dec. 30, 1924- 1,520,926

G. G. BROWN, JR

CARBURETOR VFiled April 22, 1922 y m @www Patented Dec. 30, 1924.

UNITED STATES PATENT oFFrcE.

GEORGE Gr. BROWN, J R., OF ANN ARBOR, MICHIGAN.

CARBURETOR.

Application filed April 22, 1922.` Serial No. 555,974.

dilute or lean mixtures that are heated, and

that maximum power can be obtained only by comparatively concentrated or rich mixtures supplied to the engine comparatively cold. If cold air is admitted tothe carburetor, it is necessary that more fuel be added in order to have a suiciently concentrated mixture, owing to the fact that the density of the airl increases with' a decrease of temperature. As the temperature of the mixture decreases, the mixture should be richer in order to maintain the v4velocity of reaction of the burning gases at a rate which insures an application of the explosive energy within the desired period in the cycle of movement of the piston. With the common type of carburetor, an operator, by using a dash adjustment, can regulate the mixture to make it as dilute or lean as temperature and ,load conditions permit, and thus obtain greater mileage than if he were not able to so control the mixture. The average driver, however, is not skilled in the adjustment of the carburetor to the best advantage, and therefore, is unable to use such an adjustment effectively and economically.

An object of the invention is to provide an improved carburetor for normally providing a lean, economical mixture, and adapted to provide a rich, powerful mixture when necessary or desired; with which al single manually controlled member by the extent of its movement, controls the character of the mixture under all operating conditions.; which may be advantageously combined with mechanism for automatically varying the proportions of the components of the mixture with variations in tempera" ture and load; and which is eliicientsimple, compact and relatively inexpensive. Otlier objects and advantages will be apparent from the following description of an embodiment of the invention and the novel features will l be particularly pointed out in claims.

In the accompanying drawing: Fig.- 1 is an elevation of a carburetor constructed in accordance with this invention; Fig. 2 is a sectional' elevation of the same; Fig. 3 is another sectional elevation of the same; `and Fig. 4 is asectional plan through the lower part of the carburetor.

The invention, is illustrated and described las applied to a carburetor of the type disclosed in U. S. patent to Breath No. 1,153,-

891, and also as having a thermostatic con-A trol of the fuel supply as disclosed in my copending application Serial No. 473,249, filed May 28th, 1921. The fuel is received in the float chamber 1 through fuel supply pipe 2 leading from a suitable-storage tank, not

shown. The fuel in this oat chamber is maintained at a fixed level by suitable, welllrnown float-controlled mechanism. A conduit (not shown), leads from the float chamber 1 to a passage 3 extending vertically along the casing 4 of the mixing chamber 5. A throttle drum or cylinder 6, is rotatively mounted in the mixing chamber be- 'tween a wall of the casing 4 and a removable circular wall 7 of the casing. The wall 7 is held rotatively against the casing 4by a clamping ring 8 which has a flange overlying the periphery of the wall 7 and is secured `to the casing in a Asuitable manner, such as by screws- 9 passing1 through the same and into the casing. W 9 are tightened to force the clamping ring 8 against the face of the casin 4, the wall 7 wi'll be frictionally held against rotation relatively to the casing.-

-The passage 3 at its upper end is provided with spaced ports 10 and 11 both of which open into a conically shaped recess 12 in tlie casing in whi h is rotatably mounted a tubular valve element 13 with' a tapered nose fitting in the conical recess and overlying the port 10. The tapered nose of the valve element 13 is provided with a port 14 which en the screws is adapted4 during the rotation of the valve vary the How of fuel through the passage 3 into the interior of the tubular valve element. A sleeve is rotatably mounted in an axially disposed aperture 16 of the rotatable side wall 7 of the casing. An arm 17 is provided with an aperture through which the sleeve 15 passes, and the arm is held against axial movement thereon between the wall 7 and a flange 18 at the inner end of the sleeve. The arm is keyed or otherwise secured to the sleeve 15 for rotation therewith and its ends are disposed in slots 19 in the drum 6 so as to cause rotation of the drum 6 with the sleeve 15. The valve element 13 extends axially into the lsleeve 15 and rotates relatively thereto. An extension 20 is telescopically receive within the valve element 13 and by meansof a pin 21, extending diametrically through the extension and cooperating with longitudinally extending .slots 22 in the valve element, causes a rotation of the valve element with the extension and permits a .limited axial movement of the extension relatively to the valve element. The extension is re'- duced at its outer-end and passes through a reduced bore in the sleeve to limit movement of the extension relatively to the sleeve. A throttle arm 23 is keyed or otherwise fixed upon the reduced outwardly projecting end of the sleeve 15 so as to rotate therewith. An arm 24 is keyed or otherwise fixed upon the extension 20 of the valve element soy as to rotate therewith and the arm 24 may be held against axial movement thereon in a suitable manner, such as by a nut 25' threaded upon the reduced projecting end of the extension 20. A headed'screw 26 passes through an aperture in the arm 24 and has threaded engagement with an arm 27 formed integrally with the throttle arm 23. A nut 28 is disposed upon the screw 26 between the arm 27 and the arm 24, and a spring 29 acts between the screw 28 and the arm 24 in a direction to normally cause the separation thereof and press the arm 24 against the knurled head ofthe screw 26. `When the screw 26 is rotated, the arm 24 will be adjusted toward or from the arm 27 dependent upon the direction ot rotation of the screw. The nut28 is used to control the pressure of the spring 29 against the arm 24 so that the adjustment may be made accurately and conveniently by simply turning the screw 26. When the adjustment is once properly mader the nut 25 serves as a lock nut compressing arm 24 against arm 27 and sleeve 15 thereby preventing any change in the adjustment between arms 24Mand 27. When the throttle arm 23 is given a partial rotation through a suitable connection to its upper end, it will cause a corresponding rotation of the sleeve 15, the throttle cylinder 6, and the valve element 13.

The throttle cylinder 6 is provided with Manresa a mixture outlet port 30 and an air intake port 31 at diametrically opposite points. The port 30 controls the passage of the mixture from the mixing chamber within the casing 4 into the conduit 32 through which it passes to the intake manifold. The port 31 of the cylinder controls the passage from the conduit 33 into the mixing chamber. rlhe valve element 13 is provided in its interior with a restricted axially disposed aperture 34 in which a rustro-conical governor element 35 is disposed for reciprocation endwise through the same. A head 36 upon the small end of the governor element limits the movement of the governor element in onedirection through the restricted opening 34 and the other or larger end restricts the movement of the governor element in the opposite direction. A bearing block 37 is mounted for sliding movement within the valve element endwise thereof, and a spring 38 within the valve element acts between the bearing block and the head 36 of the governor element to normally press the governor element to the right (Fig. 2) and carry the smallest portion thereof into the opening 34.

The e'ective passage` through the opening 34 is then a maximum.

A bimetal thermostat 39 is anchored at one end to the valve element, loops downwardly through a slot 40 in the element, doubles back within the element, and bears upon the end of the bearing block 37. With changes intemperature', the thermostat will either shift the block 37 in a direction to compress the spring 38, or in an opposite direction to partially release the spring 38. A spring 41 is compressed between the anchoredend of the thermostat and the extension of the valve element for normally pressing the nose of the valve element into the conical recess. An aperture 42 is provided in the wall of the conduit 33 which is normally closed by a flap valve 43. rlhis flap valve comprises a plate carried by an arm'44 that is pivoted intermediate of its ends upon a pin 45 passing through the wall of the intake conduit. rlhe free end of the arm 44 extends into the port 31 so as to be engaged and operated by an edge of the port when the throttle cylinder has been rotated in a direction to completely open the intake port 31 to the maximum extent. This operation of the flap valve uncovers the opening 42 in the intake conduit.

An auxiliary frustro-conical valve element 46 is rotatively mounted in the apex portion of the conical recess 12 andextends through the adjacent wall of the casing and is provided with an operatingy arm 47. The auxiliary element 46is recessed at its base and is provided with a port 48 leading from the recess to its outer surface which is adapted to cooperate with the port 11 of the tuel passage 3. rThe adjacent end of the valve llll element 13 is apertured as at 13a so'that when the ports 48 andll are in alignment liquid fuel may pass through the same into the recessed end of the element 46 and thence through the aperture 13a in the end of the valve element into the interior thereof. The auxiliary element 46 is used to admit fuel therethrough when starting the engine, at

which time a rich mixture is desired. The rotatable side wall 7 of the casing is provided with a lug 49 which carries an adjustable screw 50 forming a stop for the throttle arm 23. The lug 47 is adjustable with the wall 7 when the ring 8 is loosened and the wall is rotated. When the rwall 7 is clamped to the gasing the rotation of the screw 50 provides a.finer adjustment in determining the effective stopping position. The exposed portion ofthe valve element 13 within the mixing chamber is provided with apertures 5l through which the fuel passes from the interior of the valve element into themixing chamber within the throttle drum. The conduit 33 is connected to a hot air stove (not shown), which is heated in a suitable manner such as by the exhaust gases, so that the air normally entering the mixing chamber through the conduit 33 has been heated.

In the operation of the carburetor, in starting the engine, the arm 47 of the priming device is rotated to bring the port 48 of the auxiliary valve element 46 into l alignment with the port 11. The suction in the intake manifold will be communicated to the conduit 32 and thus to the mixing chamber. vThe hot air entering the intake conduit 33 passes through the port 31 of the throttle cylinder into the mixing chamber,

and concomitantly the fuel is drawn byl suction from the passage 3 through the ports 11 and 48 into the interior of the valve element and thence through the apertures 51 into the moving column of heated air. Fuel also passes through the ports 10 and 14 into the interior of the valve element. The'fuel is vaporized by the heated air and carried along into the intake'manifold. When'the engine has been started, the arm 47 is rotated to carry the port 48 out of alignment with the port 11 and the fuel is drawn into the mixing chamber solelyv through the co- .operating ports 10 and 14.

The suction communicated from the ind take manifold to the'mixing chamber causes Va movement of the ,governo-r element 35 to the left (Figure 2), so as to draw the larger portion of the governor element into the Y' aperture 34 and restrict the eective passage through the valve element to the apertures 51 and thus control the amount of fuel added to the mixing chamber. .This operation of the governor is clearly set forth in the Breath patent hereinbefore referred to j and per se forms no part of the present invention.

The greater the stress by the spring 38 upon the governor element, the less the movement of the governor element by suction in the mixing chamber, and accordingly the less restriction to the flow of the fuel through the valve element. This ther-mostatic control'per se forms the subject matter of the separate application hereinbefore referred to.

During the operation of the engine, the throttle arm 23 is manipulated to rotate the throttle cylinder and vary the effective intake aperture or port 31 in a manner well known. At the same time the valve element 13 will be rotated to shift the port 14 with respect to the fixed port 10 of the fuel passage so as to vary the fuel admitted to the mixing chamber in proportion to the amounty open position, the port 31 will be open to its fullest aperture, although not yet in alignment with the intake conduit 33 at its left side, and the maximum amount of hot air may enter the mixing chamber and the proportional amount of fuel willv be admitted through the valve element 13. The engine will then be developing the maximum power which is possible with maximum efficiency.

y If additional power is desired, the throttle arm 23- is given a slight additional movement in the opening direction which causes an edge of theport 31 to engage the projecting end of the arm 44 of the flap valve and rotate the arm to carry the flap valve 43 away from the intake conduit 33 and uncover the aperture 42. Cold air will, therefore, be admitted' directly into the intake conduit and thence into the mixing chamber. This cold air is of greater density than the hotl admit additional fuel through the valve` ele-V mentto the mixing chamber.

The size and shape of the ports 10 and 14 may be readily designed to provide the necessary change in the proportion of fuel and air during` this slight movement of the valve element. The denser air and richer mixllO -returns to the closed position and shuts off the cold air. As the excess fuel is also shut off by the same return movement of the throttle arm, the engine at once returns toits most economical operating condition. It will therefore be seen that with a single throttle arm the carburetor throughout its normal range supplies the most economical and eiiicient mixture to the engine, and when .maximum power and speed are desired, a

slight further movement of the throttle arm will cause the admission of a rich, cool and therefore powerful mixture to the engine. This additional movement which is in the same direction as that usually given to the throttle when greater power is desired, is not confusing to the motorist, or difficult to remember. The single throttle member operated in the usual manner and controlling all operations of the engine thereby eliminates the necessity of using dash adjustmcnts of the carburetor or various other adjustments which may be provided for use under varying operating conditions. ln addition, the thermostatic control of the fuel supply automatically changes the mixture proportions, with changing temperature and the governor element changes the mixture 'f proportions with changing load so that the carburetor is completely automatic in action except as the throttle member may be operated to increase the speed or power of the engine. This single and automatic control is very important since the carburetor provides maximum efficiency for engines operated by unskilled motorists and never needs adjustment after'it has once been properly set.

It will be obvious that various changes in the details and arrangements of parts herein described and `illustrated for the purpose of explaining the nature of the-invention, may be made by those skilled in the art within the principle and scope of the invention.

l claim: l

1. ln a carburetor, a mixing chamber, means for supplying liquid fuel to said chamber, a conduit for supplying hot air to said chamber, a valve controlling'the admission of fuel to the chamber, a valve controlling the quantity of air passing through said chamber, a common operating device for operating said valves concomitantly to ply conduit leading thereto, a throttle cylinvary the fuel supply with variations in the quantity of air admitted, and means operable through the common operating device adapted to admit cold air to the chamber after the air valve has been approximately completely opened and the common operating device has been given a further movement to admit more fuel to the chamber.

2. lln a carburetor, a mixing chamber, means for supplying liquid fuel to said chamber, a conduit for supplying hot air to said chamber, a valve controlling the admission of fuel to the chamber, a valve controlling the quantity of air passing through said chamber, a common operating device for operating said valves concomitantly to vary the fuel supply with variations in the quantity of air admitted, and a valve in said hot air conduit operable through the common operating device adapted to admit cold air to the chamber after the air valve has been approximately completely opened and the common operating device has been given a further movement to admit more fuel tothe chamber.

3. In a carburetor, a hot air intake conduit, a throttle device controlling said conduit, means controlled by the throttle device for admitting fuel to the intake conduit according to a predetermined ratio to provide a lean hot mixture, and means for admitting cold air to the intake conduit anterior to the admission of the fuel thereto, at approximately wide open position of the throttle device.

4. In a carburetor having a hot air intake conduit, a throttle device controlling said conduit, means for supplying fuel to the intake conduit, a valve in the intake conduit anterior to the fuel admission point, normally closed when the throttle device is in all positions less than approximately wide open, and operable by the throttle device to admit cold air directly to the intake conduit automatically when the throttle device has been opened wide.

5. ln a carburetor, a casing, a hot air supply conduit leading thereto, a throttle cylinder in said casing having a part controlling the admission of hot air from the conduit to the casing, a fuel supply device for supplying fuel to the casing, a valve controlling the admission of fuel to the casing, means for adjusta-bly coupling the throttle cylinder and fuel supply valve for supplying fuel and hot air to the casing in a determined and variable proportion, a valve in said conduit for admitting cold air thereto,

said valve being operable by the throttle cylinder when the cylinder is given a further movement after having reached approximately wide open position, whereby coldy air will be admitted to the casing with a further operation of the fuel supply valve.

6. ln a carburetor, a casing, a hot air supder in said casing having a part controlling the admission of hot airfrom the conduit to the casing, a fuel supply device for supplying fuel to the casing, a valve controlling the admission of fuel to the caslll() ing, means for adjustably coupling the throttle cylinder and fuel supply valve for supplying fuel and hot airvto the casing in a determined and variable proportion, a valve in said conduit for admitting cold air thereto, said cold air valve having an arm projecting into the path of the throttle cylinder to be automatically operated thereby be then admitted to the casing with a furj ther operation of the fuel supply valve.

In Witness whereof, I hereunto subscribe my signature.

GEORGE G. BROWN, JR. 

